Means and method for dynamically balancing incased fan blades



Oct. 12,1926. N 1,603,076 -c. H. HANSON MEAN$ AND METHOD FOR DYNAMICALLY BALANCING INCASED FAN BLADES Filed Nov. 27, 1922 Patented Oct. 12,

UNITED STA E s PATENT OFFICE.

CLINTON H. HANSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE MOTOR PLAYER COR- PORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

MEANS AND METHOD FOR DYNAMICALLY BALANCING IN CASED FAN BLADES. I

Application filed November This invention relates to the means and method of dynamically balancing rotary elements, particularly elements WhICll are mounted within an inclosed casing.

As an example of apparatus to which my invention is particularly applicable. I refer to the suction device shown in Patent No.

1,320,224, issued to George lV. Garmane that much of the objectionable noises resulting from vibration, is caused by inaccurate balancing of the rotary fan blades. The use of an inclosed casing around the fan blades as a bearing for the shaft, and also as a bafiie for the air flowing through the apparatus presents considerable difficulty 1n maintaining accurate balancing after the unit is assembled.

Accordingly, one of the objects of my-invention is the provision of means for reducin; the time usually required for dynamically balancing the rotary elements in such a suction producing unit, whereby certain in accuracies which may have developed aft-er the unit is housed in the inclosed casing may be readily corrected, without dismantling the apparatus.

I carry out the above object by providing a series of removable elements or plugs'which are positioned in spaced relation to each other on the periphery of the rotary elements, and are accessible for adjustment through an opening in the inclosed casing. The opening is so positioned in the casing that the removable elements pass in registration with the opening in their path of travel, so that access to any one of the adjusting elements may be obtained by merelyrotating the fan blade to the desired position. After adjustment is attained, the opening through the casingmay be sealed by a suitable air-tight closure.

The preferred means whereby my invention may be carried out, will be hereinafter fully set forth in the following description which pertains to the accompanying draw- 27, 1922. Serial No. 603,618.

ings. marized in the claims.

. In the drawings, Fig. 1 is an elevation of a suction producing unit having my invention embodied therein; Fig. 2 is a section taken on the correspondingly numbered line in Fig. 1.

My invention broadly is concerned with means whereby a rotary element may be dynamically balanced within an inclosed casing without dismantling the unit and without separating the members of the casing. I have shown my invention in connection with a suction producing unitwherein fan blades 8, 9 and 10 are mounted on a shaft 11 which forms an extension of the armature 12 of an electric motor. This shaft is shown as journalcd at one end at 13 in a frame 14, and at the other end at 15 in a fan casing 16. The fan casing surrounds the fan blades and provides a'passag'eway for air through the unit.

To attain ap roximate dynamic balancing of the fan blaes, the usual proceeding has been to balance the fan blade 8 on the shaft 11, thenfito add the blades 9 and 10 successively and to adjust the assembled device after each blade is added.' Then after the entire unit is balanced, the casing is fastened in position to completely inclose the suction producing means. While this method of procedure is satisfactory for approximate adjustment, nevertheless considerable time is necessitated for accurate adjustment particularly in machines where- The essential features will be sumin the rotative speed is comparatively high,

adjacent the'periphery of the blade. Access to these plugs may be had through an opening-25 at the side of the casing which opening is in registration with the'path of travel of the various openings 21 1n the fan blade.

To balance the rotary suction producing unit in accordance with my invention, it will only be necessary to obtain an approximate ing threaded openings therein, an inclosed.

balancing while the fan blades are on the shaft and outside the casing and then to obtain the accurate degree of balancing after the casing is placed. in position". This is obtainedby the insertion of a tool, such as a screw driverflfi, through the opening whereby the plugs 20 may .be readily accessible. Accurate balancing may be obtained by removing a plug from one opening and transferring it to another and the still finer adjustments are then made by screwing the properly selected plug in or out, thus moving its weight toward and away from the center, until the desired result is obtained. Then the opening 25 is sealed as by a plug as shown in Fig. 1.

It will be seen that my invention provides means whereby rotary elements may be dynamically balanced within an inclosed easing without necessitating the removal of the rotary parts and without-requiring a dismantling of the various sections of the easing. -Accordingly, by making an approxi- -mate balancing before the casing is positioned over the rotary elements, and by thereafter securing the final balancing, con siderable reduction in time required for accurate balancing is effected. In addition, the unit may be subsequently rebalanced, if

necessary after the apparatus is in service,

without removing the casing.

I claim 1. In combination, a rotary element, an inclosed casing therefor, and removable balancing members mounted on said element so as to, be movable radially with reference thereto, therein whereby said members may be rendered accessible for adjusting purposes. 2. In combination a rotary fan blade havcasing therefor, adjust-able balancing means in threaded engagement wlth said openings,

and means whereby access to said blade may said casing having an opening in the fan blade, whereby access to said openings in the fan blade may be had for balancing purposes without dismantling thecasmg.

4. In combination, a fan blade, means for rotating the blade, a casing inclosing the fan blade, a plurality of spaced threaded open ings'extending radially in the fan blade, threaded plugs adapted to be inserted in said openings, and said casing having an'opening in registration-with those on the blade whereby said plugs may be selectively adjusted through the casing opening for balancing purposes, and means for closing the opening in the casing.

5. In combination, a rotatable shaft, a plurality of fan blades mounted thereon, a casing surrounding the blades and providing a support for said shaft, said blades being approximately balanced dynamically before the shaft is journaled in the casing, one of said blades having threaded members extending radially adjacent the periphery thereof, said casinghavingan opening substantially in the same plane as the members whereby said members may be adjusted independently by radial movement with reference to the blades by a tool inserted through the opening, and a closure for said opening.

In testimony whereof, I hereunto affix my signature. I

CLINTON H. HANSON. 

